crc32.h 2.8 KB

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  1. /*
  2. * crc32.h
  3. * See linux/lib/crc32.c for license and changes
  4. */
  5. #ifndef _LINUX_CRC32_H
  6. #define _LINUX_CRC32_H
  7. #include <linux/types.h>
  8. #include <linux/bitrev.h>
  9. u32 __pure crc32_le(u32 crc, unsigned char const *p, size_t len);
  10. u32 __pure crc32_be(u32 crc, unsigned char const *p, size_t len);
  11. /**
  12. * crc32_le_combine - Combine two crc32 check values into one. For two
  13. * sequences of bytes, seq1 and seq2 with lengths len1
  14. * and len2, crc32_le() check values were calculated
  15. * for each, crc1 and crc2.
  16. *
  17. * @crc1: crc32 of the first block
  18. * @crc2: crc32 of the second block
  19. * @len2: length of the second block
  20. *
  21. * Return: The crc32_le() check value of seq1 and seq2 concatenated,
  22. * requiring only crc1, crc2, and len2. Note: If seq_full denotes
  23. * the concatenated memory area of seq1 with seq2, and crc_full
  24. * the crc32_le() value of seq_full, then crc_full ==
  25. * crc32_le_combine(crc1, crc2, len2) when crc_full was seeded
  26. * with the same initializer as crc1, and crc2 seed was 0. See
  27. * also crc32_combine_test().
  28. */
  29. u32 __attribute_const__ crc32_le_shift(u32 crc, size_t len);
  30. static inline u32 crc32_le_combine(u32 crc1, u32 crc2, size_t len2)
  31. {
  32. return crc32_le_shift(crc1, len2) ^ crc2;
  33. }
  34. u32 __pure __crc32c_le(u32 crc, unsigned char const *p, size_t len);
  35. /**
  36. * __crc32c_le_combine - Combine two crc32c check values into one. For two
  37. * sequences of bytes, seq1 and seq2 with lengths len1
  38. * and len2, __crc32c_le() check values were calculated
  39. * for each, crc1 and crc2.
  40. *
  41. * @crc1: crc32c of the first block
  42. * @crc2: crc32c of the second block
  43. * @len2: length of the second block
  44. *
  45. * Return: The __crc32c_le() check value of seq1 and seq2 concatenated,
  46. * requiring only crc1, crc2, and len2. Note: If seq_full denotes
  47. * the concatenated memory area of seq1 with seq2, and crc_full
  48. * the __crc32c_le() value of seq_full, then crc_full ==
  49. * __crc32c_le_combine(crc1, crc2, len2) when crc_full was
  50. * seeded with the same initializer as crc1, and crc2 seed
  51. * was 0. See also crc32c_combine_test().
  52. */
  53. u32 __attribute_const__ __crc32c_le_shift(u32 crc, size_t len);
  54. static inline u32 __crc32c_le_combine(u32 crc1, u32 crc2, size_t len2)
  55. {
  56. return __crc32c_le_shift(crc1, len2) ^ crc2;
  57. }
  58. #define crc32(seed, data, length) crc32_le(seed, (unsigned char const *)(data), length)
  59. /*
  60. * Helpers for hash table generation of ethernet nics:
  61. *
  62. * Ethernet sends the least significant bit of a byte first, thus crc32_le
  63. * is used. The output of crc32_le is bit reversed [most significant bit
  64. * is in bit nr 0], thus it must be reversed before use. Except for
  65. * nics that bit swap the result internally...
  66. */
  67. #define ether_crc(length, data) bitrev32(crc32_le(~0, data, length))
  68. #define ether_crc_le(length, data) crc32_le(~0, data, length)
  69. #endif /* _LINUX_CRC32_H */